KR20080037781A - Autofocus camera module - Google Patents

Abstract

An autofocus camera module is provided to reduce manufacturing cost for a camera module by designing an actuator as a simple structure consisting of upper and lower plates and an elastic supporting member. An autofocus camera module(100) includes a housing(110), a lens barrel(120), an actuator(130), and a PCB(Printed Circuit Board,140). The actuator is mounted inside the housing, controls a gap from the lens barrel with voltage applied, moves up and down, and includes upper and lower plates and an elastic supporting member(133). The elastic supporting member elastically supports the upper and lower plates. The lens barrel is inserted inside the housing from an upper opening and has lenses inside. The PCB is mounted on the lower end of the housing and includes an image sensor.

Description

Autofocus camera module {Autofocus camera module}

1 is an assembled perspective view of a camera module equipped with a conventional autofocus function.

2 is a cross-sectional view of a camera module equipped with a conventional autofocus function.

3 is a schematic assembled perspective view of an auto focus camera module according to the present invention;

4 is a cross-sectional view of the auto focus camera module according to the present invention;

<Explanation of symbols for the main parts of the drawings>

110. Housing 120. Lens Barrel

130.Actuator 131.Top

132. Bottom plate 133. Elastic members

140. Printed Circuit Board 141. Image Sensor

The present invention relates to an autofocus camera module. More specifically, an actuator configured to perform autofocus by driving the lens barrel of the camera module up and down in detail is configured in an electric field, whereby the focus adjustment control of the lens barrel is performed. It relates to an auto focus camera module that facilitates.

In recent years, with the introduction of mega pixel cameras on most portable mobile terminals, the rapid growth of the camera-mounted mobile phone market and the demand for higher resolution and higher resolution of still images and videos The demand is increasing.

Accordingly, in addition to the basic shooting functions of the camera mounted on the mobile phone, a multifunctional mobile phone capable of implementing a combination of an auto focusing function, a macro and an optical zoom function has been developed, and the camera module has been gradually miniaturized. It was rather difficult to develop a product that can satisfy various needs of consumers by making a mobile phone equipped with a focusing device assembled by a lens driving method.

In the conventional focusing apparatus, by using a plurality of longitudinal reduction gears in the DC motor, the volume becomes large and the driving noise of the motor is generated. When the DC motor is used, the start time and the stop time are long, making it difficult to control the position. Therefore, the problem that the vertical transfer efficiency of the lens assembly is significantly reduced has been pointed out.

In addition, the method using a piezoelectric actuator requires a high voltage of several tens of volts and a high frequency power of several tens of kilowatts, which complicates the driving circuit and is driven by the power transmission friction driving, which provides only less than 20% efficiency. There are disadvantages.

In order to solve such a problem, an actuator commonly referred to as VCA (Voice Coil Actuator) has been mainly used, and the lens barrel is driven up and down by the electromagnetic field generated between the coil and the permanent magnet included in the VCA. A brief technical configuration of a conventional VCM autofocus camera module is as follows.

1 is an assembled perspective view of a camera module with a conventional autofocus function, and FIG. 2 is a cross-sectional view of a camera module with a conventional autofocus function. As shown, the conventional camera module 1 includes a casing 2. And an image capturing unit 3 fixed to the casing 2 to capture an image of the subject, and a plurality of lenses 5 for projecting the image of the subject to the image capturing unit 3. The lens group 4, the lens barrel 6 for aligning the respective lenses constituting the lens group 4 in the optical axis direction, and the lens barrel 6 are driven by driving the lens barrel 6 in the optical axis direction. A driving unit 7 for performing a function of changing magnification and a function of sharpening an image captured by the image capturing unit, an initial position fixing unit for fixing the lens barrel 6 at a predetermined braking force at an initial position; To control the drive unit 7 For comprises a control unit.

The image capturing unit 3 includes an image sensor 3a for converting an optical signal of a subject through the lens group 4 into an electrical signal, a protective glass 3b for protecting the image sensor 3a, and the It consists of the board | substrate 8 with which the image sensor 3a is mounted.

The red barrel 6 is equipped with an infrared cut filter for blocking the infrared rays passing through the lens group (4).

In addition, the driving unit 7 is wound around the lens barrel 6 and is fixed to the coil 9 receiving current from the control unit, and the casing 2 fixed to the horizontal portion of the coil 9 The magnetic flux is made of a permanent magnet 10 is divided in polarity, the groove portion is formed in the casing (2) so that the coil is inserted and bonded to the groove portion so that the coil (9) does not protrude.

A yoke 11 is mounted between the permanent magnet 10 and the lens barrel 6 to circulate magnetic flux of the permanent magnet 10.

In addition, the conventional camera module 1 has a casing 2 having the lens group 4 mounted therein, a bracket 2a for supporting the casing 2, and an image sensor under the bracket 2a. And a printed circuit board 8 on which the driving circuit C, a plurality of passive elements R, and the like are mounted.

On the upper surface of the printed circuit board 8, the bracket 2a and the casing 2 are sequentially stacked and coupled, and at this time, permanently transports the lens barrel 6 mounted on the casing 2 up and down. A drive unit 7 composed of a magnet 10 and a coil 9 is mounted on a printed circuit board 8 in the casing 2, and the drive unit 7 is controlled by a drive circuit that generates a high current.

On the other hand, the lens barrel (6) inserted into the casing (2) is provided with a screw portion (6a) on the outer peripheral surface is inserted into the casing (2) and coupled by the rotation of the lens barrel (6) and at the same time the lens barrel (6) The focus adjustment for the lens group 4 in the barrel 6 is made by adjusting the height of the?

Such a conventional auto focus camera module is configured in a magnetic field method including a coil 9 and a permanent magnet 10 for driving the lens barrel 6 up and down, so that the coil 9 and It is pointed out that the technical configuration for forming the electromagnetic force between the permanent magnet 10 is not only complicated but also difficult to control the strength of the electromagnetic force generated between the coil 9 and the permanent magnet 10.

In addition, since a high current voltage is inevitably applied to the driving circuit in which the driving unit 7 for generating electromagnetic force between the coil 9 and the permanent magnet 10 is controlled, an image sensor mounted at a position adjacent to the driving circuit. There is a disadvantage that the effect of the electromagnetic waves due to the high current is emitted to (3a).

Accordingly, the present invention was devised to solve the above-mentioned disadvantages and problems in the conventional auto focus camera module, and an actuator consisting of an upper plate and a lower plate whose corresponding surfaces each form an uneven surface is used for electric field driving. By allowing the autofocus of the camera module to be adjusted, the auto-focus camera module is provided to make it easy to adjust the lens barrel's up and down feed amount by adjusting the voltage amount and to reduce the manufacturing cost with a simple configuration. There is an object of the invention.

The object of the present invention is a lens barrel in which a plurality of lenses are laminated and coupled therein, a housing in which the lens barrel is inserted and mounted at an upper center portion, and an interval between the upper plate and the lower plate is adjusted by applying a voltage to the inside of the housing. In addition, it is achieved by an autofocus camera module including an actuator in which the lens barrel is vertically transferred by adjusting the gap between the upper plate and the lower plate, and a printed circuit board mounted in close contact with an image sensor mounted at the center of the actuator.

The camera module has an electric field type actuator including an upper plate and a lower plate which are moved up and down within a predetermined range in a housing, and the gap between the lens and the image sensor is adjusted by adjusting the gap between the upper plate and the lower plate. Auto focusing is performed.

At this time, the upper plate and the lower plate constituting the actuator are perforated in the incident region through which the incident light incident through the lens of the lens barrel penetrates, respectively, the uneven surface is formed on the corresponding surface.

The upper and lower plates are doped with an electrolytic material, such as silicon, whose counterparts are capable of generating attraction due to the movement of positive and negative charges. The pole and the (-) pole are individually connected to apply a predetermined voltage.

The attraction force to attract the upper and lower plates to each other is generated by the voltage applied to the upper and lower plates, and the focus is automatically adjusted by changing the distance between the image sensor and the lens as the upper plate is moved downward with respect to the lower plate.

At this time, when the voltage of the upper plate and the lower plate is not applied, the upper plate and the lower plate are returned to their original positions by the elastic spring interposed therebetween.

On the other hand, the lower side wall of the housing is preferably formed to a length that can cover the side of the upper plate and the lower plate of the actuator so that the up and down movement of the actuator is made in the housing.

Matters concerning the operational effects, including the technical configuration of the above object of the auto focus camera module of the present invention, will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

First, Figure 3 is a schematic assembly perspective view of the auto focus camera module according to the present invention, Figure 4 is a cross-sectional view of the auto focus camera module according to the present invention.

As shown, the auto focus camera module 100 of the present invention is mounted on the upper surface of the lens barrel 120 in the housing 110, the interval is adjusted by the application of voltage, and the actuator 130 is moved up and down is mounted The printed circuit board 140 on which the image sensor 141 is mounted is tightly fixed to the lower portion of the housing 110.

The housing 112 is inserted into the lens barrel 120 in which a plurality of lenses (L) are laminated and coupled therein through an upper end, and formed into a plate shape therein, the actuator divided into an upper plate 131 and a lower plate 132. 130 is embedded, and a printed circuit board 140 is mounted at the lower end thereof.

The actuator 130 includes a plate-shaped upper plate 131 and a lower plate 132 having support portions 131a and 132a at both sides thereof, and rectangular light receiving regions 131b and 132b are perforated in the center thereof. In addition, an elastic member 133 is interposed between the upper plates 131 and the support parts 131a and 132a of the lower plate 132 to support the upper plate 131 and the lower plate 132 so as to be elastically movable.

At this time, the elastic member 133 is made of a synthetic resin material having elasticity including a compression spring.

And, the upper plate 131 and the lower plate 132 constituting the actuator 130, respectively, the corresponding surface is composed of the uneven surface (131c, 132c). This is to increase the electric field at each corner of the uneven corners of the uneven surfaces 131c and 132c when different voltages are applied to the upper and lower plates 131 and 132.

In addition, the uneven surfaces 131c and 132c are doped with an electrolytic material such as silicon having different polarities, so that the upper plate 131 and the lower plate 132 are positive and negative poles, respectively. It is configured to enable an electrical connection of the driving circuit 150 to which a predetermined voltage is applied.

On the other hand, the actuator 130 is a predetermined voltage is applied to the upper plate 131 and the lower plate 132 through a driving circuit 150 electrically connected to the (+) and (-) poles, the actuator 130 The driving circuit 150 for applying a voltage to the is configured in a switch application method or a method applied using a drive IC.

When a predetermined voltage (approximately about 2.8 v) is applied through the driving circuit 150, an attractive force is generated between the upper plate 131 and the lower plate 132 to attract the corresponding surfaces to each other.

Accordingly, the upper plate 131 and the lower plate 132 are elastically flowed while the gaps are narrowed to each other while both sides are supported by the elastic member 133 interposed therebetween, and the actuator 130 is housing As installed inside the 110, the upper plate 131 of the upper portion 131 is elastically flowed in a state where the lower plate 132 is tightly fixed to the lower portion of the housing 110.

In addition, a lens in which a plurality of lenses L are stacked on an upper portion of the upper plate 131 vertically transported by an attractive force formed by an electric field formed between the lower plate 132 and the upper plate 131 fixed to the housing 110. The lower end of the barrel 120 is directly seated, and the image sensor 141 mounted on the printed circuit board 140 is tightly coupled to the lower part of the lower plate 132 fixed in the housing 110.

As described above, the image sensor 141 fixed to the lower surface of the lens barrel 120 and the lower plate 132 seated on the upper plate 131 of the actuator 130, between the upper plate 131 and the lower plate 141. The focal length is varied by the attraction force generated in the and the focus adjustment is automatically performed by adjusting the intervals that flow in accordance with the generated intensity of the electric field generated with respect to the voltage applied to the upper plate 131 and the lower plate 141. Is done.

At this time, the strength of the electric field generated between the upper plate 131 and the lower plate 132 of the actuator 130 is made of an electrolytic material such as silicon doped on the corresponding surface of the upper plate 131 and the lower plate 132. Allow to be adjusted according to the concentration.

On the other hand, when the application of the voltage is interrupted through the drive circuit 150 connected to the actuator 130 consisting of the pair of upper plate 131 and the lower plate 132, the electric field formed in the actuator 130 is released As the upper plate 131 on the lower plate 132 is transferred to the upper by the elastic force of the elastic member 133 is returned to its original position.

The auto focus camera module 100 of the present invention having such a technical configuration has a driving circuit 150 connected to the actuator 130 in the housing 110 of a digital camera device including a mobile phone in which the camera module 100 is embedded. By being connected to the shutter, the operation of the shutter becomes an on / off function of the switch installed in the driving circuit 150, and thus autofocusing (AF) adjustment is performed when the user presses the shutter. .

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be possible, but such substitutions, changes and the like should be regarded as belonging to the following claims.

As described above, in the auto focus camera module of the present invention, the auto focus of the camera module is performed through an actuator in which the upper and lower plates whose upper and lower corresponding surfaces form the uneven surface are driven by an electric field method. Thereby, there is an advantage that the autofocus can be precisely adjusted as the electric field strength of the actuator is easily adjusted by applying the voltage through the driving circuit.

In addition, the present invention has an advantage that the manufacturing cost of the camera module can be significantly reduced because the actuator can be simply configured by only the upper and lower plates and the elastic member for elastically supporting them.

Claims (11)

A lens barrel having a plurality of lenses laminated therein; A housing in which the lens barrel is inserted and mounted at an upper center portion; An actuator in which the gap between the upper and lower plates is adjusted by applying a voltage to the inside of the housing, and the lens barrel is vertically transferred from the upper end of the housing by adjusting the gap between the upper and lower plates; And A printed circuit board having an image sensor mounted on a center portion of the actuator and tightly coupled to a lower end portion of the housing; Auto focus camera module comprising a. The method of claim 1, The auto focus camera module further includes a driving circuit having positive and negative poles on the upper and lower plates of the actuator, respectively, and a driving circuit connected to apply a predetermined voltage. The method of claim 2, The driving circuit is configured to be applied using a switch application method or a drive IC (drive IC) auto focus camera module, characterized in that the configuration. The method of claim 1 Autofocus camera module, characterized in that the lower end of the lens barrel is mounted on the upper plate of the actuator. The method of claim 1, And an upper surface of the image sensor mounted on the printed circuit board in close contact with the lower surface of the actuator. The method of claim 1, The upper plate and the lower plate of the actuator, respectively, the center of the auto focus camera module, characterized in that the incident region through which the incident light incident through the lens of the lens barrel penetrates. The method of claim 1, The upper plate and the lower plate of the actuator, the corresponding surface is formed with an uneven surface auto-focus camera module, characterized in that. The method of claim 1, The upper plate and the lower plate of the actuator, the corresponding surface is doped with an electrolytic material capable of generating attraction due to the movement of the (+), (-) charge. The method of claim 1, The actuator is provided with support portions at both sides, the auto focus camera module, characterized in that the elastic member is interposed between the support portions. The method of claim 9, The elastic member includes a compression spring, auto-focus camera module, characterized in that made of a synthetic resin material having elasticity. The method of claim 1, The housing is an autofocus camera module, characterized in that the lower side wall is formed to a length that can cover the side of the upper plate and the lower plate of the actuator.

Images